The present invention relates generally to memory cards, and more particularly, to a memory card (e.g., a multi-media card (MMC)) wherein tape or an epoxy is used to support the external signal contacts (ESC's) of the memory card leadframe structure so that the tie bars used to connect the contacts to the outer frame of the leadframe can be removed prior to the molding of the package body of the memory card.
As is well known in the electronics industry, memory cards are being used in increasing numbers to provide memory storage and other electronic functions for devices such as digital cameras, MP3 players, cellular phones, and Personal Digital Assistants. In this regard, memory cards are provided in various formats, including multi-media cards and secure digital cards.
Typically, memory cards comprise multiple integrated circuit devices or semiconductor dies. The dies are interconnected using a circuit board substrate which adds to the weight, thickness, stiffness and complexity of the card. Memory cards also include electrical contacts for providing an external interface to an insertion point or socket. These electrical contacts are typically disposed on the backside of the circuit board substrate, with the electrical connection to the dies being provided by vias which extend through the circuit board substrate.
In an effort to simplify the process steps needed to fabricate the memory card, there has been developed by Applicant a memory card wherein a leadframe assembly is used as an alternative to the circuit board substrate, as described in Applicant's co-pending U.S. application Ser. No. 09/956,190 entitled LEAD-FRAME METHOD AND ASSEMBLY FOR INTERCONNECTING CIRCUITS WITHIN A CIRCUIT MODULE filed Sep. 19, 2001, the disclosure of which is incorporated herein by reference. As is described in Ser. No. 09/956,190, the leadframe and semiconductor die of the memory card are covered with an encapsulant which hardens into a cover or body of the memory card. The body is sized and configured to meet or achieve a “form factor” for the memory card. In the completed memory card, the contacts of the leadframe are exposed within a common surface of the body, with the die pad of the leadframe and the semiconductor die mounted thereto being disposed within or covered by the body.
Memory cards, such as multi-media cards, are used by advancing the same into a host socket which includes a plurality of connector pins. Many host sockets include nine connector pins to accommodate the seven contacts included in many memory card formats such as multi-media cards, and the nine contacts included in the secure digital card memory card format. Applicant has previously determined that one of the drawbacks associated with leadframe based memory cards is that portions of the tie bars which are used to connect the contacts to the outer frame of the leadframe are typically exposed in the leading edge of the memory card which is initially advanced into the host socket. More particularly, exposed within this leading edge are the severed ends of the tie bars created as a result of the cutting or singulation process typically used to separate the outer frame of the leadframe from the remainder thereof subsequent to the formation of the body of the memory card. These exposed portions of the tie bars give rise to a potential to short against the metal features of the host socket, and are thus highly undesirable.
The present invention addresses and overcomes the above-described deficiencies of currently known leadframe based memory cards by providing a memory card wherein tape or an epoxy is used to support the contacts of the memory card leadframe structure so that the tie bars used to secure the contacts to the outer frame can be removed prior to the molding of the body of the memory card. More particularly, the tape or epoxy is applied to the leadframe, with the tie bars thereafter being punched out or otherwise removed, thus leaving the tape or epoxy to hold the contacts of the leadframe structure in place during the remaining steps of the assembly process. These and other attributes of the present invention will be described in more detail below.